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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 5 |
| 6 | 19 |
| 7 | 63 |
| 8 | 365 |
| 9 | 1199 |
| 10 | 7177 |
| 11 | 36209 |
| 12 | 295355 |
| 13 | 1652085 |
| 14 | 15193115 |
| 15 | 114570449 |
| 16 | 1323338487 |
| 17 | 8732267521 |
| 18 | 93577466255 |
| 19 | 822198823101 |
| 20 | 10952623368043 |
| 21 | 98672511931269 |
[1,1,3,5,19,63,365,1199,7177,36209,295355,1652085, 15193115,114570449,1323338487,8732267521, 93577466255,822198823101,10952623368043, 98672511931269] |